He’ll play himself in an episode titled “The Gang Saves the Day,” but specific details about the storyline have not been revealed. Groban’s appearance is sure to be fun, however, considering Dee (Kaitlin Olson) and Artemis (Artemis Pebdani) are huge “Grobanites.”

Groban’s other TV appearances include stints on “The Office,” “CSI: NY” and “Glee.”

The ninth season of “It’s Always Sunny” returns in September, when the comedy shifts from FX to its new sister network FXX.